Method and means for protecting neon signs and circuits



March 19, 1935. J. DE PUDDICOMBE METHOD AND MEANS FOR PROTECTING NEONSIGNS AND CIKCUITS Filed Aug. 51, 1932.

. INVENTIIOR- I c? d'e Paddz'co'mbe MW-6 BY r W! ATTORNEY- Patented Mar.19, 1935 METHOD AND MEANS FOR PROTECTING NEON SIGNS AND CIRCUITS Jack DePuddicombe, New York, Y. Application August '31, 1932, Serial No.631,107

11 Claims, (01. 176124) This invention relates to collectively andindividually disposed electrical conductors in which a source of supplyas of high voltage is operative, and has particular reference tomultipleand series couplings in which illuminated neon or gaseous display tubesare arranged and to provide combined protection, subsequent to partialdamage of the system.

In the neon display sign or illuminated sign field, in which a singlesource of supply, in the form of a high tension transformer or inductioncoil, is effective to transmit stepped up A. C. current to the separateletters or members of the multiple series or series multiple group, eachof these includes cooperating terminals or electrodes, in the knownmanner,and one of the objects of this invention is the provision of amethod of preventing the entire system from becoming inoperative, in theevent of a sudden breakdown or leakage in one of the letter members, ashas heretofore been the case, thereby to keep the normal letter elementsof a group illuminated.

Another object of the invention, connected with the foregoing, is theprovision of means which, when shunted across the electrodes of a singlemember, as aforesaid, may be effective to so control the current as topreclude the possibility of a breakdown in the remainder of the membersof the system. Each member is provided with such shunt means.

Another object of the present invention in the event of a breakdown ofone of the letter members of a group, is to prevent an overload on thetransformer, and to maintain the load thereon at a constant, even thoughone or more letter elements of a sign group cease to function.

Each gaseous tube or letter oifers a certain resistance between itselectrodes, and a feature of the invention is a control or safety devicewhich, when disposed in the shunt wiring, is of such conductiveproperties as to remain dormant or inac-' tive while the tube isilluminated, but which, when the tube becomes damaged or inactive fromany cause, as is frequently the case in practice,

may be effective to carry the current past the said'electrodes to acooperating or second tube, so that the latter as well as the otherunits in the assembly may be entirely free from the effect of thedamaged member and the load on the transformer kept constant, withoutdanger of shorting of the transformer and the consequent fire hazardwhich results therefrom.

. Since such former breaks in the circuit, primarily involving a singleunit of the sign, have usually, if not invariably, been accompanied by ashort circuit in the transformer, due to com-' plete out put of theentire neon sign group, a'further object of the invention is to preventthe overload of the short circuiting action, with a view to prolongingthe effective life of the transformer. 5

As a break in single members of the sign system has involved the wholeof the combined auxiliary sign members, as already indicated,inconvenience has been experienced in detecting a single damaged tube,when all of the letter members are dead and a still further object ofthis invention is to render each of the aforesaid neon sign membersvisible as they remain operative, so that the associated damaged andunlighted neon letter member may be easily visually detected for removalor replacement.

Further, if the shunt tube housing is made of lass, activity of theshunt terminals, upon breakdown of a letter may be seen by reason of thearcing of the shorting current across the gap of the shunt device.

Considerable flickering has occurred in systems of this type, asheretofore constructed, subsequent to injury or damage to one of itsunits, and yet another object of this invention is to so conduct thecurrent past the defective member as to cause entire absence offlickering, with uniform luminosity of the tubes unaffected by thebreakdown of the defective member.

With the above indicated objects and advantages in view, and otherswhich will hereinafter appear, the invention resides inthe novelconstruction, combination; arrangement and relative location of parts,which are hereinafter clearly described, and fully illustrated in theaccompanying drawing, in which:

Fig. 1 is a diagrammatic view of an electric circuit in which a sign,consisting of a number of illuminating neon tube letters in multiple,each with a separate control or shunt element, is incorporated.

Fig. 2 is a like'view, except that one of the letters is represented indamaged or inactive condition, with its associated control or shuntdevice functioning.

Fig. 3 is an elevational view of a control device, per se.

Fig. 4 is an end view of the device shown in Fig. 3, and

Fig. 5 shows a slight modification of structure, in which the lettersare connected in series multiple.

Similar characters of reference are applied to corresponding partsthroughout the various views.

The particular embodiment of the novel cir- 8B cuit control means orauxiliary tube 1 here selected for illustration includes a shell 2,which may be of any insulating material, such as glass, porcelain orfibre. Air-tightly mounted on one end of this shell, as seen in sectionin Fig. 3, is a cap which includes a member 3, and engaging the saidmember is a disk 4, which has an integral conductive perforated ear 4'.

The structure of the other end of the tube is identical with that of thefirst, so that the description is equally applicable to both. Disposedwithin the housing thus formed is a pair of conductors, each numbered 5.The outer ends of these conductors are riveted to their respective caps,as at 6, while their inner ends or electrodes, hereinafter furtherreferred to are spaced apart to form a gap '7.

As shown in Fig. 1, the transformer A includes the known primary coilwhich is supplied with alternating current from any source; andcooperating with the first coil is a secondary or high tension winding,so that the voltage is increased from 110 in the primary coil to about15,000 volts in the secondary coil and tube circuit.

Extending from the high tension coil is wiring 8, a continuation 9 ofwhich is connected with the opposite end of the coil. Between the wires8 and 9 are terminals, with which cooperating terminals or electrodes11, 12 of a gas tube or letter 10 cooperate to normally close thecircuit thereat. The tube in the present instance is formed as theletter E, and two other tubes A and T are also designated 10, so theletters form a word, as an example.

Disposed in parallel with the first letter is the second letter, therebeing a wiring portion 13 which extends from the wire 8 to the electrode11 of said second letter; and then from the other electrode 12 of theletter another wiring portion 14 connects with the wire 9. The thirdletter T is also connected in parallel, there being a wiring portion 15,which connects at 11, and another portion 16 which extends from theelectrode 12 to the wire 9.

.The gaseous circuit through a tube made luminous by the passage of ahigh tension electrical current, supplied usually by an alternatingcurrent transformer, operating on 110 volts A. C. current supply, offersa certain resistance to the output of the transformer. When the circuitthrough the gaseous tube circuit is broken, through fracture of thetransparent glass wall thereof, or leakage through the terminalelectrade on either end of the tube, which results in a change ofinternal pressure in the tube and a consequent loss of conductivity, thegaseous tube will cease to be luminous. If there is no relief circuitthen offered for the output of the transformer, it will steadilyincrease in temperature, until the heavy tar or similar plasticinsulation used generates excessive internal pressure, and finallyexplodes, with dangerous destructive actionto life and property.

The shunt circuit which I provide for each individual gaseous luminoustubing is designed to offer a moderately higher resistance to the outputof the transformer, so that when the internal circuit of the relatedtubing is properly functioning the shunt circuit will be inactive, andto instantly function when the internal circuit of the tubing is broken.There is no time lag between the period when the tubing circuit ceasesto be luminous or active, or is broken, and the time when the shuntcircuit, through the moderately higher resistance offered by the air aregap, becomes active. The substitution of the shunt circuit for thenormal luminous circuit through the gaseous tubing is instantaneous. Thedistance of the gap between the confronting ends of the electrodes ofthe shunt by-pass determines the amount of the higher resistance offeredby the shunt by-pass to the flow of the high tension current of thetransformer.

The flow of the high tension electrical current across the air arc gap,within the transparent glass tube of the shunt by-pass device, producesa luminous effect, by means of which the active shunt may be readilyand'positively detected, in a sign assembly involving many individualletter forms.

The arrangement of terminals in the wiring for each sign or letter form,with which the terminals of the associated sign or letter form tubingcooperate, affords means for 'removably mounting the individual letteror sign form, in a group assembly. But this means, in combination withthe safety shunt by-pass, combines to provide a circuit for a signassembly wherein any damaged or non-luminous sign tubing part or lettermay be withdrawn, without interrupting or breaking the circuit of theluminous sign tubing parts, and a fresh or replacement part or letterplaced in position. Due to the fact that the shunt which became activewhen the damaged tubing became inactive will also have a higher circuitresistance than the circuit of the replacement gaseous tubing, the hightension electrical current will naturally take the path of leastresistance, when the replacement tubing is placed in proper circuitrelation to the wire terminals of the removed tubing, the high tensionelectrical current will instantly flow through the substitute tubing,avoiding the shunt by-pass associated therewith. This will result, ofcourse, in the replacement tubing becoming immediately active orluminous.

This circuit arrangement and relationship of the parts of the signassembly is such, that a very quick replacement of a damaged tubing maybe made, and full luminosity develops with this replacement.

During this operation the air within the chamber of the tube, at the gap'7, becomes ionized, which lowers the electrical resistance, andprovides a current path between the electrodes of the auxiliary tube.

Each neon letter tube is provided with an auxiliary shunt tube 1. Shuntwiring portions 19, 20 connect the auxiliary shunt tube across theelectrodes of second letter 10, this being between the wires 13 and 14;and shunt portion 21 and 22, with the auxiliary shunt tube, connect thewires 15, 16 across the electrodes 11, 12 of the third letter T.

In Fig. 2 where the structure is like that already described, the neonletter is represented as broken down or inactive, and in this case thegap '7 is shown, diagrammatically as being in the act of passing thecurrent over said gap.

In the series multiple circuit, Fig. 5, wires 13' and 14' connect withthe electrodes of the second letter 10, and wires 15' and 16, onopposite sides of the electrodes of the third letter T, are effective toconnect with the wiring 9. In this case the shunt wires for theauxiliary shunt tube of the first letter 10 are the same as those ofFig. 1; wires 19' and 20' cooperate with the auxiliary shunt tube of thecenter letter, and the wires for the device 1 which is in shunt acrossthe electrodes of the tube T are represented at 21' and 22'. Thus inthis circuit all of the letters are provided with shunt tubes acrosstheir terminals in series multiple.

Considerable particularities of description, as to materials, detail ofparts, capacities and utilities are hereinbefore stated, but it will beunderstood that these statements, made with particular reference to theelements now preferred, of the many possible embodiments of theinvention which are contemplated are not in any way to be taken aslimitative of the invention. Inasmuch as many changes could be madewithout departing from the scope thereof, it is intended that all mattercontained in the foregoing descriptionor shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense. While I have shown specific embodiments of the invention, it isunderstood many changes may be made within the scope of the claims,which are to be interpreted as broadly as is consistent with the priorart. It is particularly noted that the expression neon tubes" and neongas discharge tubes is used generically to cover gas discharge tubeshaving therein neon or helium or mixtures of these and other gases, orvapors, and other similar tubes.

What I claim is:

1. In combination, a high tension circuit including, in series therein,a plurality of neon tubes and a substantially constant-voltagetransformer secondary individual to said circuit; and an arc gap deviceshunted around each of said tubes; said are gap comprising a pair ofspaced electrodes electrically connected respectively to oppositeterminals of the associated tube,and forming a non-leaking arc gap.

2. An illuminating system comprising a high tension circuit including,in series therein, a plurality of luminous neon gas discharge tubes anda substantially constant-voltage transformersecondary individual to saidcircuit and having a capacity between 3,500 and 15,000 or more volts; anarc gap device shunted around each of said tubes; said are gapcomprising a dielectric chamber filled with air substantially atatmospheric pressure; and a pair of spaced electrodes mounted in saidchamber, and electrically connected respectively to opposite terminalsof the associated tube, and forming a non-leaking arc gap.

3. A system as in claim 2 in which said chamber is a glass chamber.

4. A system as in claim 2 in which said chamber is a porcelain chamber.

. 5. A system as in claim 2 in which said chamber is a fiber chamber.

6. A system as in claim 2 in which said electrodes have substantiallycoaxially alined circular opposed inner ends having sharpcircumferential edges which cause the arc during by-' passing to passonly at a small point of each edge and to reset the arc from such pointto another small part only of the edge when said point gets hot, therebyto prevent excessive heating of the electrodes, during by-passin'g andto prevent increase of resistance of the arc during by-passing.

'7. A system as in claim 2, said gap being of such length thatthebreak-down resistance of the gap is normally slightly higher than thenormal operating resistance of the associated tube; the heating of theair in the chamber, during by-passing when a tube breaks down,decreasing the gap resistance to approximately equal the normalresistance of such tube, thereby to maintain the transformer loadapproximately con.- stant and to maintain the operative tubes in anoperative .circuit; the resistance of the gap when of said length beingat all times great enough to snuff out the are when a removed associatedtube in normal condition is replaced in the circuit.

8. A system as in claim 2, in which the breakdown resistance of said gapis normally slightly higher than the normal operating resistance of theassociated tube, the heating of the air in the chamber when a tubebreaks down and the arc persists decreasing of the gap resistance toapproximate normal resistance of the tube, thereby to maintain thetransformer load approximately constant. and the operative tubes inoperative circuit; said control devices being at all times capable ofabsorbing and dissipating the entire load of the transformer and anyincrease in power as'the voltage increases, thereby preventing excessivepotential rise and injury by the transformer to itself and preventingexcessive voltage drop around the device.

9. A system as in claim 1 in which the breakdown resistance of saidcontrol device isnor-" mally slightly higher than the normal operatingresistance of the associated tube, and decreases during by-passing toapproximate the normal resistance of such tube, thereby to maintain thetransformer load approximately constant and the operative tubes inoperative circuit; the resistance of the device being at all times greatenough to snufi out the are at the jump gap when a removed associatedtube in normal condition is replaced in the circuit; said device beingat all times capable of absorbing and dissipating the entire load of thetransformer and any increase in power as the voltage increases,

thereby preventing injury by the transformer to itself.

10. In combination, a high tension circuit having opposed terminals, aplurality of neon tubes connected in multiple between said terminals andan arc gap device shunted around each of said tubes; said arc gap devicecomprising a pair of spaced electrodes electrically connectedrespectively to opposite terminals of its associatedtube and forming anonleaking arc gap.

11. In combination, a high tension circuit including, in series therein,a plurality of neon tubes; and an arc gap device shunted around each ofsaid tubes; said arc gap device comprising a pair of spaced electrodeselectrically connected respectively to opposite terminals of theassociated tube and forming a non-leaking arc JACK PUDDICOMBE.

